The efficient electrocatalysts for hydrogen evolution reaction (HER) are indispensable. Herein, Mo₂C micropillars decorated with Pt nanoparticles (<4 nm) on Mo foil (Pt/Mo₂C-L/Mo) are synthesized by laser ablation in a focused mode in CH₄ atmosphere and laser-induced reduction in an under-focused mode in Ar/H₂ atmosphere. The Pt/Mo₂C-L/Mo possesses excellent HER performance (21 mV at 10 mA cm⁻²) and stability (1317 mA cm⁻² for 100 h) in acid media. Integrated gas diffusion and catalytic electrodes of Pt/Mo₂C-L/Mo are constructed by laser in a mixed model and used in proton exchange membrane water electrolyzer (PEMWE). The voltage of the constructed PEMWE of (−) Pt/Mo₂C-L/Mo || IrO₂/Ti (+) (1.55 V at 10 mA cm⁻²) is lower than that of (−) 20 wt.% Pt/C || IrO₂ (+) (1.69 V at 10 mA cm⁻²) for overall water splitting. This work provides a universal laser synthetic strategy of integrated electrodes with promising application in the field of hydrogen energy.